Introduction:

Gears offer an interesting study of mechanical advantage for rotational motion.

Activity:

Try the gears provided by your teacher. Figure out which one is harder to spin, and which one spins faster.

The Essence of The Gear:

• Spinning one disk makes another disk spin.
  • The teeth on one gear can make the other gear spin.
  • The chain on a bike can link the gear on the pedal to the gear on the wheel.
  • A rubber band (or fanbelt) around one disk can use traction to make another disk spin.
  • A rubber tire on one disk can use traction to make another disk spin.
• MA = (Drive Teeth or Circumference) / (Follower Teeth or Circumference)

Video of 2007 RGD

Conclusion:

Start to look for materials that could be used as simple machines! Start to collect junk for your RGD!

Enrichment:

An excellent case-study for gears can be found in the ten-speed bicycle. Can you use the idea of a "trade-off" to explain how first gear is different from tenth gear? Can you make your explanation without talking about force and distance?